Cutting shoe for bagmaking machines



June 2, 1953 D. sTANGE CUTTING SHOE FOR BAGMAKING MACHINES 2 Sheets'-Sheet l INVENToR. v

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Argom/fm June 2, 1953 D. sTANGE 2,640,540

CUTTING SHOE FOR BAGMAKING MACHINES Filed April 15, 1951 2 Sheets-Sheet 2 IN V EN TOR.

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Patented June 2, 1953 MACHINESL ljelmar Stange, Minneapolis; M irmg; assignor to' Bemis Bro. Bag Qo.,Minne`apolis, Minn.,a corporation of Missouri Claims. (c1. 164-68) My invention relates generally to machinery for making bags and more specically to improvements in apparatus for partially severing or perforating the bag material preparatory to dividing the same into bag' lengths.

More particularly, my invention relates to4 an improved cutting shoe or perforator blade of the type disclosed in the United States Patent No. 2,182,002, issued Decemberl 5, 1939.

Heretofore, cutting shoes of the above type have been fabricated from a single sheet of ma# terial, the shoe cooperating with a pair of cute ting knife equipped rolls one each operating on an opposite Working face of the shoe. Such an arrangement required that the shoe and the knife equipped rolls together with the means for mounting said rolls be manufactured to extremely close tolerances, that the means for mounting the knife equipped rollsl be adjustable, or that other adjustment means' be provided' to locate the cutting knives in proper relationship to the cutting shoe. An importantl object of my invention, therefore, is the provision of novel cutting shoe construction which will lessen the need for critical' adjustment of the knife equipped cutting rolls.

Another highly important object of my invention is the provision of a cutting shoe, as set forth, in which the tendency' toward undue wear thereof or of the cutting knives cooperating therewith is reduced to a minimum.

Still another object of my invention is the provision of novel cutting shoe' construction which will permit the bag material to be perforated or partially severed, the partially severed lengths of material being subsequently separated. l

A still further object of my invention is the provision of a cutting shoe of the abovetype which is relatively simple and inexpensive to produce, which i's eicient in operation, and which is rugged in construction and durable in use.

other highly' important objects Vand aman-- tages of my invention will become apparent from the following detailed specification, ape pended claims, and attached drawings'. x r

Referring t'o the drawings in wl'iielilike characters indicate like parts thflhlit the severalviews:

Fig. 1 is a view partly in side elevation and partly ASectionY of part df a bag making inachine incorporating my invention;

Fig. '2111s view in man 5f the' apiiaats irlutl'at in Fig; l, slh parts' Heir-ig i'klawy and some parts shown in section;

Fig. 3 is a view in section taken substantially on4 the line 3 3 of Fig. 2';

Fig. 4 is an enlarged fragmentary view in plan of my novel cutting shoe;

Fig. 5 isv a fragmentary detail in section taken on the line 5 5 ofu Fig. 4'; and

Fig. 6 is' av view in perspective illustrating a modified form of' my invention. l

Referring to the drawings with greater detail, the numeral l indicates a web of bag making material which may be assumed to be fed from a supply roll in the usual manner by suitable mechanism known to be old in the and therefore not shown. The bag material may be any of the usual` materials from which bags are made such as cellulose, cellophane, or even ordinary paper.

The web of material I, as it passes into the machine, is formed into a flat tube 2 about a former plate 3, the tubing 2 continuously advancing between pairs of upper and lower forwarding rollersl I and 5 respectively, and from thence to a pair of upper and lower perforator or cutting rolls 6 and I respectively, each of the latter carrying a cuttingknife or periorator 8. The forwarding rollers 4` and 5 as well as the cutting rolls 6 and 'I are preferably power driven at predetermined speeds by suitable mec'hanism', not shown. The cutting knives 8 during rotation of the cutting rolls 6 and 'IV c'ut or perforate opposite sides of the flat tube 2 as the tube' progresses therebetween.

yThe former plate 3 is provided with 'a longitudinally extending groove 9 in its upper face for Vthe reception of the elongated shank I IlY of a perforator or cutting shoe I I. With reference to Fig. 2, it will be seen that the cutting shoe II extends longitudinally of the machine and has itsforward end extending longitudinally beyond theV former plate 3, the widest portion of the cutting shoe being substantially equal in width to that of the former plate 3. During its initial forward movement, the tubing 2 moves forward relative to the former plate 3 and cutting shoe II.

At its forward end, the former plate 3 is bifurcated, as indicated at I2, and terminates at the cutting rolls 6 and l,` see Fig. 2. 'I'h-e cutting knives 8 carried by the rolls 6 and l extend transversely of the machine, the shape thereof depending upon the desired shape of the bag ends;

The cutting shoe II is adapted to b e reciprocated intermittently with respect to the former plate 3. The rear end of the shank I0 has rigidly mounted thereon a plate or bracket I3 which receives the lower end of a lever I4 that is pivoted intermediate its ends, as indicated at I5, to a supporting structure I6. As shown in Figs. 1 and 2, the rear upturned end of the former plate 3 is riveted or otherwise secured to the supporting structure I6, as indicated at I'I, The upper end of the lever I4 carries a roller I8 which is adapted to cooperate with a cam I9 mounted for rotation in the supporting structure I6. Oscillatory movement of the lever I4 will cause movement of the cutting shoe II in a rearward direction for a purpose which will hereinafter become apparent.

As the tube 2 advances about the former plate 3 and the cutting shoe Il, it enters between the cutting rolls 6 and I and, as the cutting knives 8 thereon are rotated into engagement with thev opposite sides of the tube 2 above and below the cutting shoe I I, the shoe II will be picked up and drawn forward at the same speed as that of the knives 8. Prior to this action, the cutting shoe I I is stationary. As the tubing 2 and the cutting shoe I I advance, the knives 8 will cut or per-forate material to provide perforations in or partially sever the same, the line of severance depending upon the shape of the knives 8.

Partial severance of the tubing 2 is effected by the provision of laterally spaced parallel slots 20 that are elongated in the direction of travel of the tubing. Obviously, when the knivesv 8 engage the tubing 2, that portion of the material overlying the slots 20 will tend to be pushed into the slots by pressure of the cutting knives 8 thereagainst and be left unperforated. It is important, particularly when making bags of cellophane or materials which are more-or-less elastic but which lack great tensile strength, that suffi-k cient unperforated material be left to enable continued drawing of the tubing 2 through the machine after perforating, inasmuch as the tubing is moving through the machine `at a high rate of speed. In some instances, if a complete severance is made across the entire width of the tube 2, and particularly if the web be of extremely light weight material, the severed portion may open up and clog the machine.

The cutting shoe II, after the operation of the cutting knives B, is retracted by the cam I9, but before the knives 8 again pick up the cutting shoe II, the cam I8 rotates out of contact with the lever mounted roller I8 so that when the knives 8 pick up the cutting shoe II, the same is free to be moved forward at the speed of the knives and the tubing. When the shoe II reaches the endof its forward stroke, the cam I9 has rotated into position fully to retract the shoe, ready for the next cycle of operation.

During the perforating or cutting operation, the tubing 2 is engaged by cooperating power driven upper and lower rollers 2| and 22 respectively, and is fed thereby between upper and lower power driven rollers 23 and 24 respectively, the former of which are equipped with cutters 25 which cut through the opposite side edges of the tubing 2. The tube 2 moves between a pair of relatively high speed rollers 26 and 2'I, the former of which is provided with a circumferentially extended notch 28 which permits intermittent gripping of the perforated tube 2, whereby to exert a sudden longitudinal tension on the tubing to divide the same into bag lengths along the line of perforations therein. If desired, a suitable trimming punch 29 may be interposed in the line of feed between the rollers 23--24 and the relatively high speed rollers 2t-2l.

'4 My improved cutting shoe II is formed from a plurality of laminae and comprises a pair of upper and lower spaced anvil elements 30 and 3I respectively, and an intervening layer of rubber or like material 32. The anvil elements 30 and 3| -are preferably made from sheet spring steel or the like whereby to present relatively hard surfaces to the action cutting knives B of the rollers B and I. The intervening layer of rubber 32 may be adhesively secured to the inner surfaces of the anvil elements 30 and 3l by any suitable means but preferably is vulcanized thereto under action of heat and pressure. The rubber layer 32 will compress or yield under the impact of the cutting knives upon their respective anvil elements 30 and 3l, but is sufliciently rm to enable said cutting knives to pierce the tubing layers between the cutting knives and the anvil elements. I have found that this arrangement has eected a substantial savings in the cost of construction of the machine in that no elaborate or complicated means for journalling the cutting rolls 6 and 'I is necessary. Furthermore, the impact of the knives 8 upon the anvil elements 30 and 3I is absorbed by the rubber layer 32 so that marring of the anvil elements and rapid dulling of the cutting edges of the knives 8 is reduced to a minimum.

With reference to Fig. l, it will be seen that the slots 20 extend through the anvil elements 30 and 3I but not into the intervening layer of rubber 32. Inasmuch as the anvil elements 30 and SI are approximately .017 inch thick, it has been found that the slots 20 need not be deeper than the thickness of said anvil elements. The slots 20 may be of any desired Width, said width normally being determined by the material from which the bags are made. If the material of the web I is of relatively high tensile strength, the

width of the slots 28 may be reduced to a minimum.

In the modified form shown in Fig. 6, I provide a cutting shoe II identical in all respects to the cutting shoe in Figs. l to 5 inclusive, except that :the spaced parallel slots 28 are omitted from the progressing between the forwarding rollers 2I and y22.

My invention has been thoroughly tested and found to be completely satisfactory for the accomplishment of the objectives set forth; and, while I have shown and described a preferred embodiment of my invention and a single modication thereof, it will be understood that the same is capable of further modification without departure from the spirit and scope of the inven- Vtion as defined in the claims.

What I claim is:

1. A cutting shoe adapted to be mounted within a flat tube of bag-form material fed between cooperating upper and lower knife equipped cut- I ting rolls, said shoe comprising a pair of spaced upper and lower anvil elements each cooperating Y with an adjacent one of said cutting rolls, and yielding means resiliently biasing said anvil elementsxagainst knife imparted movements toward each other.

2. A cutting shoe adapted to be mounted within a flat tube of bag-forming material fed between cooperating upper and lower knife equipped cutting rolls, said shoe comprising a pair of spaced upper and lower anvil elements each oooperating with an adjacent one o said cutting rolls, and a compressible member between said anvil elements biasing said elements against knife imparted movements toward each other.

3. The structure defined in claim 2 in which said compressible member comprises a sheet of rubber-like material adhesively secured to said anvil elements.

4. A cutting` shoe adapted to be mounted within a at tube of bag-forming material fed between cooperating upper and lower knife equipped cutting rolls, said shoe comprising a pair of spaced upper and lower anvil elements each cooperating with an adjacent one of said cutting rolls, and yielding means resiliently biasing said anvil elements against knife imparted movements toward each other, one of said anvil elements being provided with a slot extending therethrough, said slot being elongated in the direction of feeding movement of said tube.

5. A cutting shoe adapted to be mounted within a at tube of bag-forming material fed between cooperating upper and lower knife equipped cutting rolls, said shoe comprising a pair of spaced upper and lower plate-like anvil elements and an intervening sheet of rubber-like material adhesively secured to said anvil elements, said elements each cooperating with an adjacent one of said cutting rolls, each of said anvil elements being provided with a plurality of laterally spaced parallel slots elongated in the direction of feeding movement of said tube, said slots extending through said anvil elements.

DELMAR STANGE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,867,884 Huff July 19, 1932 2,182,002 Potdevin Dec. 5, 1939 2,247,969 Sargent et al June 24, 1941 

